147 research outputs found
Light Rail Transit Surface Options
Current interest in Light Rail Transit (LRT) is anchored in its functional and economic capabilities which derive from operations at surface street level. European cities have shown that light rail can be successfully co-located with growing automobile traffic. There are no unique forms and approaches to LRT surface operations. European experts have come up with a range of design concepts of varying cost and differing impacts on adjoining vehicular and pedestrian movements. This report reviews and illustrates the applications of many of the more successfully used design and operational concepts. Topics include design concepts using man-made or vegetation barriers to separate traffic and means to delineate and separate movements with contrasting pavement textures and curbs. Considerable coverage is given to use of modern signalized traffic control and traffic management techniques. This report also deals with an essential element of LRT surface operations, self-service or barrier-free fare collection
Immersed boundary-finite element model of fluid-structure interaction in the aortic root
It has long been recognized that aortic root elasticity helps to ensure
efficient aortic valve closure, but our understanding of the functional
importance of the elasticity and geometry of the aortic root continues to
evolve as increasingly detailed in vivo imaging data become available. Herein,
we describe fluid-structure interaction models of the aortic root, including
the aortic valve leaflets, the sinuses of Valsalva, the aortic annulus, and the
sinotubular junction, that employ a version of Peskin's immersed boundary (IB)
method with a finite element (FE) description of the structural elasticity. We
develop both an idealized model of the root with three-fold symmetry of the
aortic sinuses and valve leaflets, and a more realistic model that accounts for
the differences in the sizes of the left, right, and noncoronary sinuses and
corresponding valve cusps. As in earlier work, we use fiber-based models of the
valve leaflets, but this study extends earlier IB models of the aortic root by
employing incompressible hyperelastic models of the mechanics of the sinuses
and ascending aorta using a constitutive law fit to experimental data from
human aortic root tissue. In vivo pressure loading is accounted for by a
backwards displacement method that determines the unloaded configurations of
the root models. Our models yield realistic cardiac output at physiological
pressures, with low transvalvular pressure differences during forward flow,
minimal regurgitation during valve closure, and realistic pressure loads when
the valve is closed during diastole. Further, results from high-resolution
computations demonstrate that IB models of the aortic valve are able to produce
essentially grid-converged dynamics at practical grid spacings for the
high-Reynolds number flows of the aortic root
Overweight, Obesity and Underweight Is Associated with Adverse Psychosocial and Physical Health Outcomes among 7-Year-Old Children: The 'Be Active, Eat Right' Study
Background:Limited studies have reported on associations between overweight, and physical and psychosocial health outcomes among younger children. This study evaluates associations between overweight, obesity and underweight in 5-year-old children, and parent-reported health outcomes at age 7 years.Methods:Data were used from the 'Be active, eat right' study. Height and weight were measured at 5 and 7 years. Parents reported on child physical and psychosocial health outcomes (e.g. respiratory symptoms, general health, happiness, insecurity and adverse treatment). Regression models, adjusted for potential confounders, were fitted to predict health outcomes at age 7 years.Results:The baseline study sample consisted of 2,372 children mean age 5.8 (SD 0.4) years; 6.2% overweight, 1.6% obese and 15.0% underweight. Based on parent-report, overweight, obese and underweight children had an odds ratio (OR) of 5.70 (95% CI: 4.10 to 7.92), 35.34 (95% CI: 19.16; 65.17) and 1.39 (95% CI: 1.05 to 1.84), respectively, for being treated adversely compared to normal weight children. Compared to children with a low stable body mass index (BMI), parents of children with a high stable BMI reported their child to have an OR of 3.87 (95% CI: 1.75 to 8.54) for visiting the general practitioner once or more, an OR of 15.94 (95% CI: 10.75 to 23.64) for being treated adversely, and an OR of 16.35 (95% CI: 11.08 to 24.36) for feeling insecure.Conclusion:This study shows that overweight, obesity and underweight at 5 years of age is associated with more parent-reported adverse treatment of the child. Qualitative research examining underlying mechanisms is recommended. Healthcare providers should be aware of the possible adverse effects of childhood overweight and also relative underweight, and provide parents and children with appropriate counseling
Using formative research to develop the healthy eating component of the CHANGE! school-based curriculum intervention
Background: Childhood obesity is a significant public health concern. Many intervention studies have attempted
to combat childhood obesity, often in the absence of formative or preparatory work. This study describes the
healthy eating component of the formative phase of the Children’s Health Activity and Nutrition: Get Educated!
(CHANGE!) project. The aim of the present study was to gather qualitative focus group and interview data
regarding healthy eating particularly in relation to enabling and influencing factors, barriers and knowledge in
children and adults (parents and teachers) from schools within the CHANGE! programme to provide populationspecific
evidence to inform the subsequent intervention design.
Methods: Semi-structured focus group interviews were conducted with children, parents and teachers across 11
primary schools in the Wigan borough of North West England. Sixty children (N = 24 boys), 33 parents (N = 4 male)
and 10 teachers (N = 4 male) participated in the study. Interview questions were structured around the PRECEDE
phases of the PRECEDE-PROCEED model. Interviews were transcribed verbatim and analysed using the pen-profiling
technique.
Results: The pen-profiles revealed that children’s knowledge of healthy eating was generally good, specifically
many children were aware that fruit and vegetable consumption was ‘healthy’ (N = 46). Adults’ knowledge was also
good, including restricting fatty foods, promoting fruit and vegetable intake, and maintaining a balanced diet. The
important role parents play in children’s eating behaviours and food intake was evident. The emerging themes
relating to barriers to healthy eating showed that external drivers such as advertising, the preferred sensory
experience of “unhealthy” foods, and food being used as a reward may play a role in preventing healthy eating.
Conclusions: Data suggest that; knowledge related to diet composition was not a barrier per se to healthy eating,
and education showing how to translate knowledge into behavior or action is required. The key themes that
emerged through the focus groups and pen-profiling data analysis technique will be used to inform and tailor the
healthy eating component of the CHANGE! intervention study.
Trial registration: Current Controlled Trials ISRCTN03863885
Keywords: Nutrition, Childhood obesity, Pen-profiles, Health, School
Fontes alternativas de energia para máquinas agrícolas.
Objetivando a reducao do consumo de oleo diesel na exploracao agricola brasileira, atualmente estimada em cerca de 3,8 bilhoes de litros por ano, a EMBRAPA iniciou programas de pesquisa e desenvolvimento a partir de 1981 em fontes alternativas de energia que pudessem apresentar viabilidades tecnicas e economicas na substituicao de oleo diesel em tratores, colhedeiras e conjuntos estacionarios de irrigacao e geracao de energia eletrica. Testes com tratores a alcool, com motores de ciclo Otto, empregando alcool hidratado produzido em microdestilarias tem demonstrado otima eficiencia e durabilidade. Tratores com motores do ciclo Diesel, trabalhando em sistema dual oleo diesel/gasogenio tem mostrado resultados satisfatorio para o emprego agricola. O emprego de gasogenio ou lenha e/ou carvao vegetal para acionar moto-bombas de irrigacao e conjuntos geradores indicam ser alternativas viaveis tecnica e economicamente, com a introducao de algumas inovacoes tecnologicas nos sistemas de limpeza dos gases. Testes estao sendo conduzidos com tratores providos de motores do ciclo Diesel em dupla alimentacao oleo diesel/alcool, com resultados altamente satisfatorios. Iniciam-se testes de uma frota experimental de tratores para utilizarem esteres etilicos de oleos vegetais em substituicao total ao oleo diesel
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